1. Place a rack in the center of the oven and preheat the oven to 350 degrees F.
Generously grease two 9-inch round cake pans with solid vegetable shortening,
then dust with flour. Shake out the excess flour. Set the pans aside.

2. Melt the white chocolate in a small glass bowl in the microwave oven on high
power for 1 minute. Remove the bowl from the oven and stir with a small rubber
spatula until it is smooth.

3. Place the cake mix, water, oil, whole eggs, egg whites, lemon juice, and
lemon zest in a large mixing bowl. Pour in the slightly cooled white chocolate.
Blend with an electric mixer on low speed for 1 minute. Stop the machine and
scrape down the sides of the bowl with a rubber spatula. Increase the mixer
speed to medium and beat 2 minutes more, scraping down the sides again if
needed. The batter should look well combined. Divide the batter evenly between
the prepared pans, smoothing it out with the rubber spatula. Place the pans in
the oven side by side.

4. Bake the cakes until they are golden brown and spring back when lightly
pressed with your finger, 28 to 32 minutes. Remove the pans from the oven and
place them on wire racks to cool for 10 minutes. Run a dinner knife around the
edge of each layer and invert each onto a rack, then invert again onto another
rack so that the cakes are right side up. Allow to cool completely, 30 minutes
more.

6. Place one cake layer, right side up, on a serving platter. Spread the top
with the lemon curd. Place the second layer, right side up, on top of the first
layer and frost the top and sides of the cake with frosting.

Place this cake, uncovered or in a cake saver, in the refrigerator until the
frosting sets, 20 minutes. Then store it, in a cake saver or under a glass dome,
at room temperature for up to 3 days, or in the refrigerator for up to 1 week.
Or freeze it, wrapped in aluminum foil or in a cake saver, for up to 6 months.
Thaw the cake overnight in the refrigerator before serving.

1. Place the white chocolate in a small glass bowl in the microwave oven on high
power for 1 minute. Remove the bowl from the oven and stir with a wooden spoon
or a rubber spatula until it is smooth. Set the chocolate aside to cool.

2. Place the cream cheese and butter in a large mixing bowl. Beat with an
electric mixer on low speed until well combined, 30 seconds. Stop the machine.
Add the lemon juice, lemon zest, and melted white chocolate, and blend on low
speed until just combined, 30 seconds. Add the confectioners' sugar and blend on
low speed until the sugar is incorporated, 30 seconds. Increase the mixer speed
to medium and beat until the frosting is fluffy, 1 minute or more.